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txn.go
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txn.go
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package mdb
/*
#cgo CFLAGS: -pthread -W -Wall -Wno-unused-parameter -Wbad-function-cast -O2 -g
#include <stdlib.h>
#include <stdio.h>
#include "lmdb.h"
*/
import "C"
import (
"bytes"
"encoding/gob"
"math"
"runtime"
"unsafe"
)
// DBIOpen Database Flags
const (
REVERSEKEY = C.MDB_REVERSEKEY // use reverse string keys
DUPSORT = C.MDB_DUPSORT // use sorted duplicates
INTEGERKEY = C.MDB_INTEGERKEY // numeric keys in native byte order. The keys must all be of the same size.
DUPFIXED = C.MDB_DUPFIXED // with DUPSORT, sorted dup items have fixed size
INTEGERDUP = C.MDB_INTEGERDUP // with DUPSORT, dups are numeric in native byte order
REVERSEDUP = C.MDB_REVERSEDUP // with DUPSORT, use reverse string dups
CREATE = C.MDB_CREATE // create DB if not already existing
)
// put flags
const (
NODUPDATA = C.MDB_NODUPDATA
NOOVERWRITE = C.MDB_NOOVERWRITE
RESERVE = C.MDB_RESERVE
APPEND = C.MDB_APPEND
APPENDDUP = C.MDB_APPENDDUP
)
// Txn is Opaque structure for a transaction handle.
// All database operations require a transaction handle.
// Transactions may be read-only or read-write.
type Txn struct {
_txn *C.MDB_txn
}
func (txn *Txn) Commit() error {
ret := C.mdb_txn_commit(txn._txn)
runtime.UnlockOSThread()
if ret != SUCCESS {
return Errno(ret)
}
return nil
}
func (txn *Txn) Abort() {
C.mdb_txn_abort(txn._txn)
runtime.UnlockOSThread()
txn._txn = nil
}
func (txn *Txn) Reset() {
C.mdb_txn_reset(txn._txn)
}
func (txn *Txn) Renew() error {
ret := C.mdb_txn_renew(txn._txn)
if ret != SUCCESS {
return Errno(ret)
}
return nil
}
func (txn *Txn) DBIOpen(name *string, flags uint) (DBI, error) {
var _dbi C.MDB_dbi
var cname *C.char
if name == nil {
cname = nil
} else {
cname = C.CString(*name)
defer C.free(unsafe.Pointer(cname))
}
ret := C.mdb_dbi_open(txn._txn, cname, C.uint(flags), &_dbi)
if ret != SUCCESS {
return DBI(math.NaN()), Errno(ret)
}
return DBI(_dbi), nil
}
func (txn *Txn) Stat(dbi DBI) (*Stat, error) {
var _stat C.MDB_stat
ret := C.mdb_stat(txn._txn, C.MDB_dbi(dbi), &_stat)
if ret != SUCCESS {
return nil, Errno(ret)
}
stat := Stat{PSize: uint(_stat.ms_psize),
Depth: uint(_stat.ms_depth),
BranchPages: uint64(_stat.ms_branch_pages),
LeafPages: uint64(_stat.ms_leaf_pages),
OwerflowPages: uint64(_stat.ms_overflow_pages),
Entries: uint64(_stat.ms_entries)}
return &stat, nil
}
func (txn *Txn) Drop(dbi DBI, del int) error {
ret := C.mdb_drop(txn._txn, C.MDB_dbi(dbi), C.int(del))
if ret != SUCCESS {
return Errno(ret)
}
return nil
}
func (txn *Txn) Get(dbi DBI, key []byte) ([]byte, error) {
ckey := &C.MDB_val{mv_size: C.size_t(len(key)),
mv_data: unsafe.Pointer(&key[0])}
var cval C.MDB_val
ret := C.mdb_get(txn._txn, C.MDB_dbi(dbi), ckey, &cval)
if ret != SUCCESS {
return nil, Errno(ret)
}
val := C.GoBytes(cval.mv_data, C.int(cval.mv_size))
return val, nil
}
func (txn *Txn) GetGo(dbi DBI, key, val interface{}) error {
var key_buffer bytes.Buffer
encoder := gob.NewEncoder(&key_buffer)
err := encoder.Encode(key)
if err != nil {
return err
}
gkey := key_buffer.Bytes()
var bval []byte
val, err = txn.Get(dbi, gkey)
if err != nil {
return err
}
val_buffer := bytes.NewReader(bval)
decoder := gob.NewDecoder(val_buffer)
err = decoder.Decode(val)
if err != nil {
return err
}
return nil
}
func (txn *Txn) Put(dbi DBI, key []byte, val []byte, flags uint) error {
ckey := &C.MDB_val{mv_size: C.size_t(len(key)),
mv_data: unsafe.Pointer(&key[0])}
cval := &C.MDB_val{mv_size: C.size_t(len(val)),
mv_data: unsafe.Pointer(&val[0])}
ret := C.mdb_put(txn._txn, C.MDB_dbi(dbi), ckey, cval, C.uint(flags))
if ret != SUCCESS {
return Errno(ret)
}
return nil
}
func (txn *Txn) PutGo(dbi DBI, key, val interface{}, flags uint) error {
var bkey bytes.Buffer
encoder := gob.NewEncoder(&bkey)
err := encoder.Encode(key)
if err != nil {
return err
}
var bval bytes.Buffer
encoder = gob.NewEncoder(&bval)
err = encoder.Encode(val)
if err != nil {
return err
}
return txn.Put(dbi, bkey.Bytes(), bval.Bytes(), flags)
}
func (txn *Txn) Del(dbi DBI, key, val []byte) error {
ckey := &C.MDB_val{mv_size: C.size_t(len(key)),
mv_data: unsafe.Pointer(&key[0])}
var cval *C.MDB_val
if val == nil {
cval = nil
} else {
cval = &C.MDB_val{mv_size: C.size_t(len(val)),
mv_data: unsafe.Pointer(&val[0])}
}
ret := C.mdb_del(txn._txn, C.MDB_dbi(dbi), ckey, cval)
if ret != SUCCESS {
return Errno(ret)
}
return nil
}
func (txn *Txn) DelGo(dbi DBI, key, val interface{}) error {
var bkey bytes.Buffer
encoder := gob.NewEncoder(&bkey)
err := encoder.Encode(key)
if err != nil {
return err
}
var bval []byte
if val == nil {
bval = nil
} else {
var val_buffer bytes.Buffer
encoder = gob.NewEncoder(&val_buffer)
err = encoder.Encode(val)
if err != nil {
return err
}
bval = val_buffer.Bytes()
}
return txn.Del(dbi, bkey.Bytes(), bval)
}
type Cursor struct {
_cursor *C.MDB_cursor
}
func (txn *Txn) CursorOpen(dbi DBI) (*Cursor, error) {
var _cursor *C.MDB_cursor
ret := C.mdb_cursor_open(txn._txn, C.MDB_dbi(dbi), &_cursor)
if ret != SUCCESS {
return nil, Errno(ret)
}
return &Cursor{_cursor}, nil
}
func (txn *Txn) CursorRenew(cursor *Cursor) error {
ret := C.mdb_cursor_renew(txn._txn, cursor._cursor)
if ret != SUCCESS {
return Errno(ret)
}
return nil
}
/*
type CmpFunc func(a, b []byte) int
func (txn *Txn) SetCompare(dbi DBI, cmp CmpFunc) error {
f := func(a, b *C.MDB_val) C.int {
ga := C.GoBytes(a.mv_data, C.int(a.mv_size))
gb := C.GoBytes(a.mv_data, C.int(a.mv_size))
return C.int(cmp(ga, gb))
}
ret := C.mdb_set_compare(txn._txn, C.MDB_dbi(dbi), *unsafe.Pointer(&f))
if ret != SUCCESS {
return Errno(ret)
}
return nil
}
*/
// func (txn *Txn) SetDupSort(dbi DBI, comp *C.MDB_comp_func) error
// func (txn *Txn) SetRelFunc(dbi DBI, rel *C.MDB_rel_func) error
// func (txn *Txn) SetRelCtx(dbi DBI, void *) error